The goal of this core is to provide the investigators involved in this program project, state of the art digital imaging fluorescence microscopy. This includes live cell imaging of B and T cells undergoing apoptosis;rises in intracellular Ca2+, analyzing the movement of proteins tagged with GFP or other fluorochromes;measurement of FRET;analysis of protein translocations in fixed cells;determination of the efficiency of shRNA constructs and multiparameter analysis in apoptotic cells. This core will be used by projects 2 and 3 and Core C and is essential for the successful completion of the proposed Aims described therein.